A tense scene is unfolding in Oakland right now as protesters, attempting to reclaim the plaza from which they were evicted early this morning, face off with police—who’ve used tear gas and percussion grenades on the occupiers.

The Occupy Oakland encampment in Frank Ogawa Plaza—renamed Oscar Grant Plaza by its new residents—was kicked out by Oakland police using smoke grenades on Tuesday morning over what authorities claimed were “sanitary and public safety concerns.” At least 75 people were arrested in the process, and protesters say three were hurt. “I think we allowed people to exercise their rights to free speech and free assembly,” OPD Chief Howard Jordan told reporters.

Update: Alternet’s Josh Holland reports that 500 people have been tear-gassed; others on Twitter say flash-bangs and percussion grenades have been used as well. Live helicopter camera feeds from ABC and CBS were apparently cut off right before the police threw the gas grenades. (Update:They’re back!) Left, a picture of riot cops in gas masks via @jankyhellface.